Wound treatment apparatus and method

ABSTRACT

Apparatuses and methods for treating wounds are disclosed. An apparatus for treating wounds is disclosed comprising an instrument for generating a low temperature, atmospheric pressure plasma, a means of flowing gas comprising mixing an inert gas and a reactive gas through the instrument, and a means of contacting the wound with the reactive gases flowing out of the instrument. A method for treating wounds using reactive gases is disclosed. The use of atmospheric pressure plasmas for treating wounds is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/539,784, filed Oct. 9, 2006, by Robert F. Hicks, entitled “WOUNDTREATEMENT DEVICE AND METHOD,” which is incorporated by reference hereinand which application claims the benefit under 35 U.S.C. §119(e) of thefollowing U.S. provisional patent application, which is incorporated byreference herein:

U.S. Provisional Patent Application No. 60/724,579, filed Oct. 7, 2005,and entitled “WOUND TREATMENT DEVICE AND METHOD”, by Robert F. Hicks.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is related to methods and apparatuses for treatinginfections in living tissue, such as may occur in wounds. Particularly,the invention is related to methods and apparatuses for promoting woundhealing by utilizing low temperature, atmospheric pressure plasmas. Theinvention also is related to a new use of atmospheric pressure plasmasfor living tissue treatment.

2. Description of the Related Art

Wounds are a major source of infection. Once infected, wounds healslowly, and if not treated aggressively can lead to amputation and evendeath. Recently, it was reported that in Pennsylvania alone, over 11,600hospital patients became infected, leading to an additional 1,500 deathsand $2 billion in hospital charges (see e.g., USA Today, Jul. 13, 2005,page 3B). There are many different types of wounds, including surgicalwounds, burns, ulcers, compound fractures, bedsores, and tissuenecroses. Chronic skin ulcers are common in patients with reduced bloodcirculation due to diabetes mellitus, atherosclerosis, arteriosclerosisobliterans, Buerger's disease, and excessive radiation therapy. Skinulcers are highly susceptible to infection. Infected wounds can causesecondary infections in other parts of the body, such as in the bone orbone marrow in osteomyelitis.

Soldiers receive complicated invasive wounds from gunshots, incendiarydevices, improvised explosive devices (IEDs), land mines, and many othertypes of ordinance. Infection can set in at any time as the soldier ismoved from the battlefield to the field hospital to recovery facilities.Once infected, battlefield wounds heal slowly, and treatment is apainful, prolonged process.

A variety of bacteria can invade wounds and prevent them from healing.These bacteria may be classified as gram-positive or gram-negative, andas obligate aerobes, facultative anaerobes, microaerophilic, or obligateanaerobes (see Gladwin and Trattler, in “Clinical Microbiology MadeRidiculously Simple,” MedMaster, Inc., Miami, Fla., 2004). Among these,the microorganisms most likely to infect tissue, including skin andbone, are Streptococcus pyogenes, Staphylococcus aureus, Clostridiumperfringens, and Pseudomonas aeruginosa. Skin infections fromStreptococcus and Staphylococcus can result in impetigo, cellulitis,abscesses, furuncles, and carbuncles. Streptococcus can enter deepwounds and spread rapidly through the fascia between the skin tissue andmuscle, causing Necrotizing Fasciitis, a condition that results in skindeath and is often fatal. Clostridium perfringens, otherwise known asGas Gangrene, invades deep wounds with dead tissue, where an anaerobicenvironment exists. This infection used to be common among soldierswounded in battle.

Pseudomonas aeruginosa is common in hospitals, infecting sick patientswith weak immune systems. This bacterium is a gram-negative, obligateaerobe. It is resistant to nearly all antibiotics. Diabetic patientshave an increased risk of developing foot ulcers colonized withPseudomonas, and it can penetrate into the bone causing osteomyelitis.This bacterium is very common in burned tissue, infecting over ⅕^(th) ofall burn victims (see Kluytmans, “Surgical infections including burns,”in Prevention and Control of Nosocomial Infections, Wenzel, ed.,Williams and Wilkins, Baltimore, Md., 1997). If not eradicated, thisinfection eventually leads to fatal sepsis. Another microorganism thatcan similarly infect burns is Pseudomonas cepacia.

When bacteria invade wounds, they can quickly develop into a biofilm(see Wolcott, “Biofilm Based Wound Care,” Southwest Regional Wound CareCenter, Lubbock, Tex., 2005). A biofilm is a multicellular organism withstrong defenses that makes eradication difficult, and is one of the mainreasons chronic wounds do not heal (see Costerton, Stewart, andGreenberg, “Bacterial Biofilms: A common cause of persistentinfections,” Science, Vol. 284, p. 1318, 1999). Pseudomonas aeruginosais an excellent example of biofilm forming bacterium, and is why thisinfection is so tenacious in ulcers and burned tissue. In order totreat, biofilm-based infections in wounds, a multi-pronged approach isneeded that includes mechanical debridement (cutting and scraping),antibiotics, and topical antimicrobial agents. The former technique canbe painful for the patient, and the wound can become infected againshortly after treatment. Moreover, bacteria are constantly evolving andin some cases are showing increased resistance to antibiotics andantimicrobial agents. Therefore, it is clear that new treatments arenecessary to kill bacteria that invade wounds, and to further assist thebody in the healing process.

Over the past several years, it has been shown that bacteria can bedestroyed by exposure to atmospheric pressure plasmas (see for example,Laroussi, IEEE Transactions on Plasma Science, Vol. 30, p. 1409, 2002;Kelly-Wintenberg, Montie, et al., Journal of Industrial Microbiology andBiotechnology, Vol. 20, p. 69, 1998; and Herrmann, Henins, et al.,Physics of Plasmas Vol. 6, p. 2284, 1999). The gas in these plasmas isweakly ionized so that the temperature remains low, i.e., near ambientconditions. In these studies, atmospheric pressure plasmas have beenused to kill microorganisms dispersed on gel or glass media. Researchershave found that the effectiveness of the technique varies widelydepending on the culture medium and how it is prepared, the specificplasma device used, and the method of plasma generation. Note that noneof these studies focused on bacteria commonly found in wounds. In onecase, the treatment of biofilms with atmospheric pressure plasma wasexamined (see Joaquin, Abramzon, and Brelles-Mariño “Gas DischargePlasmas as a Novel Approach to Destroy Bacterial Biofilms,” Applicationsin Environmental Microbiology, submitted in 2005). The researchers foundthat exposure of Rhizobium gallicum biofilm to the plasma for 5.0minutes killed from 96.9 to 99.9% of the colony forming units.

A group of Russian researchers have shown that treatment of purulentwounds in rats with gaseous nitric oxide reduced healing time by 32%compared to the control group (see Shekhter, Serezhenkov, et al.,“Beneficial effect of gaseous nitric oxide on the healing of skinwounds,” Nitric Oxide, Vol. 12, p. 210, 2005). The nitric oxide wasdispensed onto the wound at levels near 1000 ppm, and was produced usingan air plasma device. These authors stated that they have treated over10,000 patients with a wide variety of skin wounds, finding that gaseousnitric oxide promotes wound healing in most cases. Nevertheless, NOtreatment of wounds has not proven to be effective in studies conductedin the United States, and in some cases, such as in burn injury, itcould be detrimental to the patient (see Soejima, Traber, et al., “Roleof Nitric Oxide in Vascular Permeability after Combined Burns and SmokeInhalation Injury,” American Journal of Respiratory and Critical CareMedicine, Vol. 163, p. 745, 2001).

Due to the widespread infection of wounds, and their annual toll onhuman life, not to mention the enormous costs to the medical professionand society in general, there is a great need in the art to develop moreeffective methods of treating these injuries. These and other needs aremet by the present invention as described in detail hereafter.

SUMMARY OF THE INVENTION

To overcome the limitations in the prior art discussed above, and toovercome other limitations that will become apparent upon reading andunderstanding the specification, various embodiments of the presentinvention are directed to an apparatus for treating wounds, a method oftreating wounds with gaseous radicals and other reactive species, and anew use of atmospheric pressure plasmas for wound treatment. The woundtreatment apparatus comprises an instrument for generating a lowtemperature, atmospheric pressure plasma with a gas beam containing ahigh concentration of reactive species, such as oxygen radicals, and ameans of contacting the wound with the gas beam, wherein the wound isbathed in the reactive species contained with in the gas beam. Theradicals and other reactive species will kill bacteria present in thewound, destroy bacterial biofilms, and promote the healing of damagedtissue.

The method of treating wounds comprises flowing gas containingmolecules, such as oxygen, through a device that is capable ofdissociating the molecules into radicals and other reactive species,then directing the gas flow, which is rich in the radicals and otherreactive species, out of the device and towards a wound, and exposingthe wound to the reactive gas for a sufficient period of time to cause atherapeutic effect. The new use of atmospheric pressure plasmascomprises applying the reactive species generated in these devices tothe direct treatment of wounds in skin, bone and other organs for thepurposes of sterilization and promotion of the healing process.

One exemplary embodiment of the present invention is a wound treatmentdevice that bathes the wound in reactive species, such as oxygen orhydroxyl radicals, at temperatures that are compatible for exposure toskin and other organs. This device comprises an instrument thatgenerates a low temperature, atmospheric pressure plasma, wherein theradicals and other reactive species formed in the plasma flow out of theinstrument in such a way that they come in direct contact with thewound. A particularly well-suited instrument for this embodiment is onethat may be held in the hand or easily manipulated by the hand over thesurface of the wound.

A further embodiment of the invention is an apparatus that comprises alow temperature, atmospheric pressure plasma with a gas beam containingradicals and other reactive species, and a fixture that mounts theplasma instrument directly above the wound surface, wherein thephysician or medical technician is provided with a convenient andeffective means of bathing the wound in the reactive species generatedby the plasma. In a preferred embodiment the fixture may be detachedfrom the instrument and disposed of so that there is no possibility oftransferring bacteria from one patient to another. In another preferredembodiment the fixture may be detached from the instrument andsterilized for reuse on patients.

Another exemplary embodiment of the present invention is a method oftreating wounds comprising flowing gas containing molecules, such asoxygen, through an atmospheric pressure plasma device that is capable ofdissociating the molecules into radicals and other reactive species, forexample O atoms, then directing the gas flow out of the device andtowards a wound, and exposing the wound to the gas containing thereactive species for a sufficient period of time to kill bacteria andbacterial biofilms, and promote the healing of the wound. A particularlyadvantageous embodiment is where the plasma is generated in the vicinityof the outlet of the device so that a high concentration of radicals andother reactive species contacts the wound and effectively kills thebacteria and accelerates the healing process.

In a further embodiment of the invention, the instrument for generatinggaseous reactive species is combined with a spray device so that thewound may be intermittently bathed with the gaseous reactive species andwith a saline solution or a therapeutic chemical compound that helpspromote wound healing. In this embodiment, the wound treatment apparatuscomprises an instrument for generating a low temperature, atmosphericpressure plasma with a gas beam containing a high concentration ofreactive species, a spray system for introducing a saline solution or atherapeutic chemical compound, a means of contacting the wound with thegas beam, and a means of contacting the wound with the spray solution,wherein the wound is alternately bathed in the gaseous reactive speciesand the saline solution or the therapeutic chemical compound.

In another embodiment, the invention comprises a method of woundtreatment comprising flowing gas containing molecules through a devicethat converts the molecules into radicals and other reactive species,flowing the gas rich in the radicals and reactive species over the woundfor a sufficient period of time, then briefly contacting the wound witha saline solution or a therapeutic compound, such as an antimicrobialagent, and repeating this procedure for one or more times, wherein thewound is sterilized and treated to promote the healing process. Theseand other embodiments of the present invention will be furtherunderstood upon inspection of the drawings and the accompanyingdescription.

A typical embodiment of the invention comprises a plasma generatingdevice for producing a flow of gas comprising at least one reactive gasspecies in a low temperature, atmospheric pressure plasma, the flow ofgas comprising mixing an inert gas and a reactive gas provided by a gasflow system, and a nozzle coupled to the plasma generating device fordelivering the at least one reactive gas species to a wound. The lowtemperature, atmospheric plasma is typically generated by applying radiofrequency power to at least one of closely spaced electrodes sufficientto breakdown the gas and form a capacitive discharge, the closely spacedelectrodes comprising a first surface of a first electrode and a secondsurface of a second electrode machined into the same shape forming auniform gap between the surfaces in contact with the gas flow where thelow temperature, atmospheric pressure plasma is generated. The inert gasmay be selected from the group consisting of argon and helium. The atleast on reactive gas species typically comprises oxygen containing gasmolecules and the reactive gas may be selected from the group consistingof air, carbon dioxide, carbon monoxide, nitrous oxide, ammonia, andwater. The gas flow may comprise mixing 0.1 to 10.0 volume % of thereactive gas in the inert gas. A control unit may be coupled to theplasma generating device for supplying a rate and gas composition of thegas flow and electric power to the plasma generating device forgenerating the at least one reactive gas species. The control unit maybe operated such that the at least one reactive gas species has atransit time from the nozzle to the wound of less than about 50milliseconds.

A gas flow system may be used to provide the flow of the gas to theplasma generating device. The gas flow system may incorporate acompressor and/or tanks of compressed inert gases (e.g. argon) andoxygen gas and one or more metering valves to control the gascomposition and flow rate. For example, the at least one reactive gasspecies may be selected from the group consisting of oxygen atoms,nitrogen atoms, hydrogen atoms, and hydroxyl radicals. In addition, theapparatus can employ an electrical power supply coupled to the plasmagenerating device for generating the at least one reactive gas species(e.g. through application of a high frequency voltage applied across thegas flow).

The nozzle for delivering the at least one reactive gas species to thewound may comprise a shape selected from the group consisting of a disc,a rectangle, a cone and a hemisphere. The shape has at least one openingfor the reactive gas species to flow out. The disc and hemisphericalshapes may have a plurality of holes. The rectangular shape may have aslit. The cylindrical shape may have a single hole. In addition, adetachable end cap over the nozzle may be used for protecting the woundfrom cross-contamination among different patients.

Further embodiments of the invention may also employ the plasmagenerating device as a hand-held device held and manipulated by a userto deliver the at least one reactive gas species to the wound of apatient. Other embodiments may incorporate a robotic arm coupled to theplasma generating device for scanning the at least one reactive gasspecies over the wound.

Some embodiments may also utilize a control unit coupled to the plasmagenerating device for supplying the gas flow and gas composition andelectric power to the plasma generating device for generating the atleast one reactive gas species.

In still further embodiments, an internal cooling system may be usedcomprising a cooling fluid circulating around the nozzle to cool theflow of the gas. The cooling system reduces the temperature of thedelivered reactive gas species contacting the wound.

In yet further embodiments, an exhaust gas system may be used fordrawing any potentially harmful gases in the gas flow including the atleast one reactive gas species away from a patient with the wound.

In addition, embodiments of the invention may employ a proximity sensorfor providing a feedback signal indicating proximity of the nozzle tothe wound. The proximity sensor allows an operator to confirm that anadequate supply of the at least one reactive gas species is delivered tothe wound as the reactive gas dissipates quickly outside a relativelyshort effective range.

In still further embodiments of the invention, the nozzle mayincorporate a chemical outlet for delivering a chemical compound to thewound. The at least one reactive gas species may be selected to causethe chemical compound to bond to cells of the wound.

In a similar manner, a typical method embodiment of the invention maycomprise flowing a gas comprising mixing an inert gas and a reactive gasprovided by a gas flow system, generating a low temperature, atmosphericpressure plasma with a plasma generating device, forming in the lowtemperature, atmospheric pressure plasma at least one reactive gasspecies, and delivering the at least one reactive gas species to a woundthrough a nozzle coupled to the plasma generating device. Methodembodiments of the invention may be further modified consistent withapparatus embodiments of the invention described herein.

In addition, another exemplary apparatus embodiment of the invention maycomprise a means for flowing a gas comprising mixing an inert gas and areactive gas, a means for generating a low temperature, atmosphericpressure plasma from the flowing gas that contains at least one reactivegas species, and a means for delivering the at least one reactive gasspecies to a wound. The low temperature, atmospheric plasma is generatedby applying radio frequency power to at least one of closely spacedelectrodes sufficient to breakdown the gas and form a capacitivedischarge, the closely spaced electrodes comprising a first surface of afirst electrode and a second surface of a second electrode machined intothe same shape forming a uniform gap between the surfaces in contactwith the gas flow where the low temperature, atmospheric pressure plasmais generated. This apparatus embodiment of the invention may be furthermodified consistent with other apparatus and method embodiments of theinvention described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of the wound treatment apparatus in accordancewith the present invention;

FIG. 2 is a schematic of the wound treatment apparatus in accordancewith the present invention;

FIG. 3 shows schematics of different wound treatment apparatuses with(a) circular, (b) linear, (c) small-spot, and (d) hemispherical plasmabeams;

FIG. 4 is a drawing illustrating how a doctor or medical technician mayuse the wound treatment apparatus on an injured patient;

FIG. 5 is a drawing illustrating how a doctor or medical technician mayuse the wound treatment apparatus on a patient with a wound covering alarge area, such as might occur with an extensive burn.

FIG. 6 is a schematic of a wound treatment apparatus equipped with ameans of cooling the plasma generator;

FIG. 7 is a schematic of a wound treatment apparatus equipped with adetachable fixture to prevent cross contamination between patients;

FIG. 8 is a schematic of a wound treatment apparatus equipped with anexhaust gas containment system;

FIG. 9 is a schematic of a wound treatment apparatus equipped with asensor for detecting the distance between the gas outlet of theapparatus and the wound surface;

FIG. 10 shows a drawing of a wound treatment apparatus equipped with ameans of both bathing the wound in the plasma and dispensing a chemicalcompound onto the wound;

FIG. 11 is a schematic of a wound treatment apparatus that incorporatesmultiple elements according to the present invention.

DETAILED DESCRIPTION

In the following description including the preferred embodiment,reference is made to the accompanying drawings, which form a parthereof, and in which is shown by way of illustration a specificembodiment in which the invention may be practiced. It is to beunderstood that other embodiments may be utilized and structural changesmay be made without departing from the scope of the present invention.

1.0 Overview

FIG. 1 shows a block diagram of an exemplary embodiment of the presentinvention. The apparatus comprises an instrument 101 for generating alow temperature, atmospheric pressure plasma coupled to a means 102 forflowing gas containing molecules through the instrument 101, and a means103 of contacting the wound with the reactive gas species generated inthe plasma. For the purposes of the present invention reactive gasspecies include, but are not limited to, radicals, ions, ground-stateatoms, or metastable molecules. The instrument for generating the lowtemperature, atmospheric pressure plasma generally comprises electrodesthat are connected to an electrical power source. The power source canprovide a DC voltage, an AC voltage, or a high-frequency voltageoperating from 5 kHz to 500 MHz. The electrodes are arranged in such away and the voltage is supplied at a sufficiently high value, such thatthe gas is partially ionized and converted into the low temperature,atmospheric pressure plasma, i.e. comprising at least one reactive gasspecies.

The means 102 for flowing gas containing molecules through theinstrument 101 comprises a source of one or more gases that ispressurized above atmospheric pressure, or a means of pressurizing asource of one or more gases above atmospheric pressure, a device forcontrolling the flow of one or more gases, a means of mixing the gasesif more than one in used, and tubing or piping that connects the mixed,flowing gases to the instrument 101. An exemplary embodiment of themeans 102 comprises a source of air, a compressor to increase thepressure of air above atmospheric pressure, a metering valve thatregulates the flow of air, and that delivers the air from the compressorthrough the metering valve and into the instrument 101. Anotherexemplary embodiment of the means 102 comprises a tank of compressedinert gas, such as argon, a second tank of compressed oxygen gas,pressure regulators attached to each tank to ensure delivery of thegases at a constant pressure above atmospheric pressure, a meteringvalve that regulates the flow of inert gas, a second metering valve thatregulates the flow of oxygen gas, a “tee” fitting that combines theinert gas and oxygen flows together, and tubing that delivers the gasesfrom the pressure regulators through the metering valves and into theinstrument 101. Other fitting and devices may be added to otherwiseimprove the means of flowing gas to the instrument, such as a purifier,filter, flow sensor, check valve, and pneumatic on and off valves, andwill be understood by those skilled in the art.

The means 103 of contacting the wound with the reactive gas speciesgenerated in the plasma entails configuring the instrument in such a waythat the transit time of the reactive gas species from the exit of theplasma device to the wound is short enough to prevent the reactive gasspecies from being converted back into stable molecules prior toimpinging on the wound. The transit time is generally less than 0.05seconds, and preferably less than 0.01 seconds (10.0 milliseconds). Themeans 103 of contacting the wound with the reactive gas speciesgenerated in the plasma may be accomplished in many different ways. Anexemplary means comprises generating the plasma just prior to the gasoutlet from the instrument 101, placing the outlet of the instrumentabove the wound at a distance of 0.1 to 10.0 cm, and providingsufficient gas velocity at the outlet that the transit time from theinstrument 101 to the wound is less than 0.05 seconds, and preferablyless than about 10.0 milliseconds. The means of placing the instrumentabove the wound may comprise holding it with the hand, mounting it in afixture that can be positioned over the wound, mounting it in a roboticmechanism that may be controlled with a computer, or inserting it in afixture that can be attached to the patient around the area of thewound. Other means of placing the instrument above the wound may be usedwithout deviating from the scope of the present invention, and would beobvious to those skilled in the art.

Some embodiments of the invention may be implemented usinglow-temperature atmospheric plasma devices and methods taught in U.S.patent application Ser. No. 11/227,724 by Penelon et al., filed Sep. 9,2005 and entitled “LOW TEMPERATURE, ATMOSPHERIC PRESSURE PLASMAGENERATION AND APPLICATIONS,” and U.S. patent application Ser. No.11/532,749 by Babayan et al., filed Sep. 18, 2006 and entitled“LOW-TEMPERATURE, CONVERGING, REACTIVE GAS SOURCE AND METHOD OF USE,”which are both incorporated by reference herein. Particularly, devicesare taught which can be used to contact a wound with at least onereactive gas species with an adequately short transit time to enhanceeffectiveness of the treatment. U.S. patent application Ser. No.11/532,749 teaches closely spaced electrodes may comprise a surface of acurved electrode (i.e. a first electrode) and surface of a housing (i.e.a second electrode) machined into the same shape forming a uniform gapbetween the surfaces in contact with the gas flow where the lowtemperature, atmospheric pressure plasma is generated.

2.0 Wound Treatment Apparatus

A schematic of the wound treatment apparatus in accordance with thepresent invention is shown in FIG. 2. In this figure, theself-contained, low temperature, atmospheric pressure plasma source 1 isconnected via a flexible cable 8 to an electrical power supply 2 thatreceives electricity from a standard AC outlet 3. It is advantageousthat the housing of the plasma source 1 be grounded 9, so that there isno danger of electrical shock to the user of the apparatus. The plasmasource 1 is also connected via flexible tubing 7 to a gas flow system 4that is supplied with inert gas through feed line 5 and with oxygen gasthrough feed line 6. Examples of inert gas include, but are not limitedto, argon and helium. Other reactive gases that may be supplied to theplasma through feed line 6 include, but are not limited to, air, carbondioxide, carbon monoxide, hydrogen, nitrogen, nitrous oxide, ammonia,and water. Note that the electrical power supply 2 and the gas flowsystem 4 may be combined in a single control box for convenience. Thelow temperature, atmospheric pressure plasma 1 is positioned within afew centimeters of the wound 11 on a patient's arm 12. Reactive gas 10from the plasma source 1 bathes the wound 11, killing bacteria andtreating the wound to promote healing.

Exemplary embodiments of the present invention are presented in FIG. 3.The self-contained, low temperature, atmospheric pressure plasma may beconfigured in a variety of different shapes and sizes, depending uponthe type and size of wound to be treated. In schematic 3(a), the devicehousing 13 exhibits a cylindrical shape and contains a gas outlet nozzle14 that is disk shaped and has a plurality of holes in it. Other typesof perforations may be machined into the outlet nozzle 14, such asellipses, triangles, polygons, slits and annular rings without deviatingfrom the scope of the present invention. The purpose of the disk shapednozzle 14 is that is produces a shower of reactive gas 10 that is evenlydistributed over the area of the wound. The diameter of the cylindricalhousing 13 and nozzle 14 may vary from about 0.5 cm to about 6.0 cm,depending on the area of the wound to be treated, as will be understoodby those skilled in the art. The gas feed and electrical signal to theplasma source are introduced through the tubing 7 and the cable 8,respectively. Also, the housing is grounded 9. During operation of thedevice, the reactive gas 10 generated by the plasma is passed over thewound to sterilize and promote healing.

In schematic 3(b), the device housing 15 has a rectangular shape andcontains a gas outlet nozzle 16 that has a slit in it. This designgenerates a linear curtain of reactive gas 10 that can be swept back andforth over the wound. Other perforations may be machined into the outletnozzle 16 to produce the desired linear curtain of reactive gas, withoutdeviating from the scope of the present invention. These perforationsmay be a series of holes in a row that are round, square, triangular,rectangular, polygonal, or irregularly shaped. In addition, there may bemore than one row of perforations, generating more than one linearcurtain of reactive gas 10. The width of the rectangular housing 13 andin turn the slit in the nozzle 16 may vary from about 0.5 cm to about10.0 cm, depending on the area of the wound to be treated, and would beobvious to those skilled in the art. The gas is fed to the devicethrough tubing 7, the electrical signal is introduced through cable 8,and the housing is grounded 9.

In schematic 3(c), the device housing 17 exhibits a cylindrical shapeand comprises a gas outlet nozzle 18 that has a single, small hole. Thediameter of the nozzle 18 may be made small, less than 5.0 mm, andpreferably less than 2.0 mm, in order to treat a small spot on thepatient with the reactive gas 10. In a preferred embodiment of thepresent invention, the diameter of the housing 17 may be made small andlengthened, if necessary, so that the device may be inserted inside apatient to treat an internal wound, such as might be found in cases ofosteomyelitis. The outlet hole in the nozzle 18 may have shapes otherthan a circular disk, including, but not limited to ellipses, slits,triangles, rectangles, polygons, and annular rings. The gas feed andelectrical signal are introduced through the tubing 7 and the cable 8,and the housing is grounded 9.

In schematic 3(d), the device housing 19 is cylindrically shaped andcontains a gas outlet nozzle 20 that is hemispherical and has aplurality of holes in it. This design causes the reactive gas producedin the plasma to flow out in a radial direction over the surface of thehemisphere. Other types of perforations may be machined into thehemispherical outlet nozzle 20, such as ellipses, triangles, squares,polygons, and slits, without deviating from the scope of the presentinvention. The purpose of this design is to treat the interior surfaceof a deep wound, by inserting the nozzle 20 down inside the wound. Sincethe reactive gas 10 flows out in all directions, it will efficientlytreat the exposed wound surfaces. The diameter of the housing 19 and thenozzle 20 may be made small, less than 5.0 mm, and preferably less than2.0 mm, in order to insert the device inside a patient to treat aninternal wound. Here as well, the gas is fed to the device throughtubing 7, the electrical signal is introduced through cable 8, and thehousing is grounded 9.

3.0 Treating an Injured Patient with the Wound Treatment Apparatus

In one embodiment of the present invention, the wound treatmentapparatus comprises a handheld tool for treating injured patients. Adrawing showing a physician or medical technician employing theinvention in this embodiment is shown in FIG. 4. The physician 25 istreating an ulcer 27 on the calf of a patient 26, such as might occur ina person with diabetes mellitus. The handheld device 21 is operated witha control unit 24 that provides a means of flowing gas through thedevice and a means of supplying an electrical voltage to the devicesufficient to generate the plasma from the flowing gas. The tubing 23connects the gas flow from the control unit 24 to the device 21. Thecable 22 connects the electrical signal from the control unit 24 to thedevice 21. The physician 25 waves the wound treatment device 21 directlyover the ulcer 27 bathing it in the reactive species generated from theplasma, thereby killing bacteria present in the wound, and aiding thehealing process.

A schematic of an exemplary wound treatment apparatus configured fortreating a patient with a wound covering a significant part of theirbody is presented in FIG. 5. The patient 35 has a severe burn 37 thatextends over a large portion of the left leg. The patient 35 is lying onan examination table 36, so that the low temperature, atmosphericpressure plasma device 28 can scan over the burned area. The device 28is attached to a telescoping robotic arm 29, which is in turn attachedto a ceiling mounted, x-y translation system 30. The robot arm 29 andx-y translation system 30 may be computer controlled to scan in aprecise manner over the affected area, and thereby provide the optimaltherapeutic effect. The physician or medical technician assists thisprocess by positioning the patient 35 on the table 36 and entering theinstrument scanning parameters into the computer. In addition, thedevice 28 may be equipped with sensors that automatically adjust theapparatus's position above the wound through a feedback control system.

A control unit 31 is connected to the device 28 through flexible lines32. The control unit 31 supplies the device 28 with the gas flow rate,gas composition and electrical power needed to operate the plasma. Gasis supplied to the system through the gas inlet 33, whereas electricityis provided by the AC power cord 34.

4.0 Wound Treatment Apparatus with Internal Cooling System

In one embodiment of the present invention, the wound treatmentapparatus is provided with an internal cooling system as shown in FIG.6. The purpose of the internal cooling system is to provide a means ofcooling the flow of gas exiting the plasma so that it can be maintainedat a temperature close to that of the patient. Although the exampleshown in FIG. 6 is for a rectangular device with a linear reactive gasbeam 10, the internal cooling system could be equally well adapted toatmospheric plasma sources (and/or nozzles) of any size or shape,including but not limited to, cylindrical housings with disk-shaped,small spot, or hemispherical nozzles as shown in FIG. 3. The rectangularhousing 15 is configured with a gas inlet 7, electrical input 8, ground9, and reactive gas outlet 38. The cooling system comprises an internalflow channel 39, inlet 40 and outlet 41.

The cooling fluid may be any gas or liquid that is supplied at or belowroom temperature. For example, air from a compressor may be supplied tothe inlet 40. Alternatively, chilled water may be used to cool thedevice by connecting the inlet 40 and outlet 41 to a recirculating bath.The internal flow channel is placed near the outlet of the housing 15,so that it can cool the gas as it passes through the plasma and out theoutlet slit 38. This ensures that the reactive gas beam is cooled mosteffectively. Other designs may accomplish the same means withoutdeparting from the scope of the present invention, as will be understoodby those skilled in the art.

5.0 Wound Treatment Apparatus with Detachable Fixture

Another exemplary embodiment of the wound treatment apparatus is shownin FIG. 7. Here, the device for generating the plasma has a detachableend cap 43 that protects the patient from cross contamination. Thecylindrical housing 42 has a larger diameter than the nozzle 14 so thatthere is a notched region 64 that inserts inside the end cap 43. Thenozzle 44 of the end cap 43 is designed so that the holes match up withthose on the nozzle 14 on the body of the plasma source. This ensuresthat the reactive gas beam is unimpeded upon flowing out of the device.The end cap 43 is held in place with spring-loaded buttons 46distributed around the outside of the notched region 64. A button 45 onthe housing 42 is depressed to retract the buttons 46 and allow the endcap 43 to be released from the device. The device is equipped with thegas inlet 7, electrical input 8, and ground 9 to enable operation of thelow temperature, atmospheric pressure plasma.

The end cap 43 can be made of a metal, ceramic, or plastic material, andcan be disposable so that it is only used on one patient. In this way,there is no way that microorganisms can be transferred from one patientto the next when using the wound treatment apparatus. In anotherembodiment, the end cap 43 can be made for use several times on the samepatient with a simple cleaning of the end cap between uses. In yetanother embodiment, the end cap 43 can be made for repeated use withsterilization of the end cap in an autoclave between uses. Sterilizationwill prevent bacteria from one patient's wound from cross-contaminatinganother patient's wound. It is envisioned that the doctor or medicaltechnician will want to keep a number of end caps on hand, and alwaysuse a freshly sterilized one on each patient. It may be that thedisposal end cap is the best approach to guarantee that there is nocross-contamination among patients.

The removable end cap 43 may be designed in a number of different wayswithout deviating from the scope of the present invention. The end cap43 may be constructed to fit onto a cylindrical, elliptical,rectangular, square, or any arbitrarily shaped wound treatmentapparatus. Preferably, the size and shape of the end cap 43 should beengineered to fit snuggly onto the wound treatment apparatus and have anozzle design 44 that mates with the device nozzle 14 in such a way thatthe flow of reactive gas out of the device is not blocked by the end cap43. Many different means of attaching and releasing the end cap from thewound treatment apparatus may be employed, including a set screw, metalor plastic clip, spring clamp, threaded connection, snap, and otherconnecting elements as will be understood by those skilled in the art.

6.0 Wound Treatment Apparatus with Exhaust Gas System

Shown in FIG. 8 is a schematic of a wound treatment apparatus thatincorporates a means of exhausting the gas from the plasma away from thepatient and the room where the treatment is being performed. The purposeof the exhaust gas system is to ensure that the patient and theenvironment are not exposed to any potentially harmful gas moleculesthat are produced from the reactive species formed in the plasma. Forexample, air plasmas may produce ozone and nitric oxide, both of whichcan be harmful to humans if inhaled in sufficient quantity.Incorporation of an exhaust gas system into the wound treatmentapparatus prevents exposure of the patient to any potentially harmfulgases. The need for an exhaust gas system will depend upon theparticular gas and/or byproducts in the particular application as willbe understood by those skilled in the art.

In FIG. 8, the device 1 housing the low temperature, atmosphericpressure plasma is suspended above the wound 11 in the patient's arm 12.The device 1 is connected to an electrical power supply 2 via cable 8,and to a gas flow system 4 via flexible tubing 7. The electrical powersupply is connected to a source of electricity with the power line 3.The gas flow system 4 has two gas supply lines 5 and 6, which forexample, may be used to introduce helium and oxygen. The reactive gas 10emanating from the plasma bathes the wound 11, killing bacteria andtreating the wound to accelerate the healing process. Reactive gasflowing over the wound is pulled down through the holes 48 in thetreatment table 47. A housing 49 encases the holes 48 so that the gas issubstantially pumped away through a blower 50 and into a line 51 thatexhausts the gas outside the room.

Other means of incorporating an exhaust gas system into the woundtreatment apparatus may be devised without deviating from the scope ofthe present invention. For example, instead of connecting the blower 50to the table 47 with holes 48, one may place a flexible duct on the endof the blower. Then the physician or technician can hold or mount theduct below the wound 11, while the plasma device 1 is suspended aboveit. In this way, the reactive gases 10 will flow out over the wound 11and then be pulled down into the duct, and exhausted from the room.

7.0 Wound Treatment Apparatus with Sensor

In another embodiment of the present invention, the wound treatmentapparatus may be equipped with a sensor to detect the distance of theapparatus from the wound surface. Since the reactive species generatedby the plasma (including but not limited to radicals, ions, ground-stateatoms or metastable molecules) decay rapidly upon exiting the plasma, itis important to hold the wound treatment apparatus within a fewcentimeters of the wound. This makes sure that a sufficient number ofreactive species impinge on the wound to provide the therapeutic effect.Shown in FIG. 9 is a schematic of a wound treatment apparatus thatincorporates a sensor. The proximity sensor 52 is mounted on the nozzleplate 16 of the rectangular plasma source housing 15. The sensor 52views the wound in the same direction that the reactive gas 10 isflowing. The sensor 52 is connected to a computer through a cable 53.The computer receives the electrical signal from the sensor 52,interprets this data, and determines if the apparatus is being heldwithin the desired distance from the wound. One may mount onto thehousing 15 light-emitting diodes 54 and an audible horn 55 that notifiesthe operator when the apparatus is being held too far away from thewound to be effective. Many different types of sensors may be used todetect, record and notify the operator of the distance between theapparatus and the wound without deviating from the scope of the presentinvention, and will be understood by those skilled in the art.

8.0 Wound Treatment Apparatus with Plasma and Means of DispensingChemical Compound

Another exemplary embodiment of the present invention is presented inFIG. 10. Here, the wound treatment apparatus combines a low temperature,atmospheric pressure plasma with a means of dispensing a chemicalcompound (B) onto the wound. The cylindrical device housing 59 containsinternal electrodes for generating the plasma, a gas inlet 7, electricalinput 8 that attaches the power supply to the electrodes, ground 9,inlet 60 for chemical compound B, and outlet nozzle 61. The outletnozzle 61 is configured with two sets of holes: one set 62 for theplasma effluent, and a second set 63 for the chemical compound B. Insidethe housing 59 and the nozzle 61 there are means of separatelydelivering the gas to the plasma and the outlet holes 62, and thechemical compound to the outlet holes 63.

The advantages of the embodiment disclosed in FIG. 10 is that the woundmay be bathed alternately in the plasma reactive species 10, and in atherapeutic chemical compound B, thereby providing a more effectivetreatment. For example, the oxygen plasma generates O atoms andmetastable O₂ molecules plus a small amount of heat. The flow of dry,warm gas over the wound tends to dry it out. To prevent the wound fromdrying out too much, chemical compound B may be a saline solution thatis intermittently dispensed onto the wound from the apparatus. Inanother embodiment of the present invention, chemical compound B may bean antimicrobial agent or a drug that when deposited on the woundincreases the destruction rate of bacteria, and accelerates the rate ofwound healing.

In yet another embodiment of the present invention, chemical compound Bmay be a specific molecule that is designed to react with microorganismsand skin tissue that have been activated by exposure to the plasma. Itis known that oxygen atoms and other radicals generated in atmosphericpressure plasmas react with polymer surfaces, creating oxygenated groupsthat alter the surface energy. Microorganisms and skin tissue arecomposed of large organic molecules that have a composition andstructure that is similar to that of polymers. Therefore, brief exposureof microorganisms and skin tissue to the oxygen plasma will cause theirsurfaces to be covered with oxygenated groups. These groups can furtherreact with drug molecules, causing them to strongly bond to the cellmembranes. In the case of harmful bacteria, the drug molecules can bedesigned to be lethal to the organism once they are attached to the cellmembrane. In the case of skin tissue, the drug molecules can be designedto deliver proteins and enzymes that will rejuvenate the cells, causingthe wound to heal faster.

The schematic in FIG. 10 depicts one embodiment of the present inventionfor wound treatment by atmospheric pressure plasma combined with othertopical chemical or drug therapies. This embodiment integrates theplasma and compound B delivery into one apparatus. Many otherembodiments may be used without deviating from the scope of the presentinvention. For example, delivery of the plasma and the chemical compoundB to the wound may be accomplished with separate apparatuses. Thechemical compound B, e.g., saline solution, may be delivered to thewound through the use of a sterile gauze pad, an aerosol spray device, aneedle and syringe, or any other practical instrument that would beobvious to those skilled in the art.

9.0 Wound Treatment Apparatus with Multiple Embodiments

The wound treatment apparatus may incorporate multiple embodiments ofthe present invention as depicted in FIG. 11. This wound treatmentapparatus comprises a low temperature, atmospheric pressure plasma in arectangular housing 15 that generates a linear reactive gas beam 10. Theapparatus has the following additional embodiments: a detachable end cap56 to eliminate the potential for spreading infection among differentpatients; an internal cooling system 39, 40 and 41 that keeps thetemperature of the plasma gas close to that of the patient; and a sensor52 that is connected to a computer and assists with maintaining theproper distance of the apparatus from the wound. Further embodiments ofthe invention, or alternative combinations and permutations of thevarious features of embodiments of the invention described herein may beemployed without deviating from the scope of the present invention.

Note that the end cap 56 is designed to fit snuggly onto the outletnozzle 16, and it contains a slit 57 that is at least as large as thegas flow slit in the outlet nozzle 16. The end cap 56 also has a holethat permits the sensor 52 to have an unobstructed view of the wound.Spring-loaded buttons 46 are distributed around the outside of theoutlet nozzle 16. The button 45 on the housing 15 is depressed toretract the buttons 46 and allow the end cap 56 to be released from thedevice. The sensor 52 is connected to a computer through the cable 53.The computer receives the electrical signal from the sensor 52,interprets this data, and determines if the device is being held withinthe desired distance from the wound. In addition, the housing 15contains light-emitting diodes 54 and an audible horn 55 that notifiesthe operator when the apparatus is being held too far away from thewound. Finally, the cooling medium, such as chilled water, is circulatedinto the housing 15 through the inlet port 40, down the flow channel 39,and out through the outlet port 41. As part of the atmospheric plasmageneration system, the device contains a gas inlet 7, electrical input8, and ground 9.

An exemplary embodiment of the present invention is for the woundtreatment apparatus to contain the following elements: an outlet nozzlethat effectively contacts the wound with the reactive gas speciesgenerated in the plasma; an internal cooling system; an end cap toprevent cross-contamination; a sensor to assist the operator withholding the device the proper distance from the wound, and an exhaustgas containment system to prevent exposure of patients or personnel togas molecules, such as ozone, produced by the plasma. Another preferredembodiment of the present invention is for the wound treatment apparatusto contain these elements: a low temperature, atmospheric pressureplasma with effective outlet nozzle; an internal cooling system, an endcap, a sensor, an exhaust gas containment system, and a robotic stagethat automatically translates the apparatus over the surface area of thewound.

10.0 Method of Treating Wounds

A further embodiment of the present invention is a method of treatingwounds that comprises (1) flowing gas containing molecules through adevice that converts the molecules into radicals and other reactivespecies, (2) directing the gas flow, rich in radicals and other reactivespecies, out of the device and onto the wound, and (3) exposing thewound to the reactive species for a sufficient period of time to cause atherapeutic effect. The therapeutic effect may include killing bacteria,destroying bacterial biofilms, and stimulating regeneration of thedamaged tissue.

Gas molecules that are suitable for the invention include but are notlimited to oxygen, carbon dioxide, carbon monoxide, nitrogen, nitrousoxide, ammonia and water. These molecules may be converted intoground-state atoms, radicals, ions or metastable molecules that areeffective for wound treatment. Oxygen containing gas molecules, such asO₂, CO₂, and N₂O, are particularly well suited for the presentinvention, because they may be converted into ground-state O atoms,which among other beneficial properties are effective agents for killingbacteria. An advantageous means of generating ground-state atoms andradicals is to feed a mixture of 0.1 to 10.0 volume % of the gasmolecules in an inert gas, i.e., helium or argon, to the low-temperatureplasma device. The inert gas stabilizes the plasma and maximizes theproduction of atoms and radicals for the treatment of wounds. Forexample, a particularly effective wound treatment method would be tofeed argon and 0.1 to 10.0 volume % oxygen, carbon dioxide, or nitrousoxide to a low-temperature plasma device, and exposing the wound to thereactive gas species that are generated in the plasma for a timesufficient to provide the therapeutic effect.

An exemplary embodiment of the present invention comprises a method ofwound treatment with reactive species contained in flowing gas, whereina low temperature, atmospheric pressure plasma is used to generate thereactive species. Atmospheric pressure plasmas suitable for the presentinvention include those that generate a substantially high concentrationof ground-state atoms, radicals, ions, or metastable moleculesdownstream of the plasma generation zone, since the treatment methodcomprises exposing the wound to said reactive species. Atmosphericpressure plasmas that produce substantially stable molecules, such asnitric oxide or ozone, are not suitable for the present invention.

Another exemplary embodiment of the invention comprises a method ofwound treatment with flowing reactive gas species, wherein hot filamentsare used to generate the reactive species. When hot filaments are usedfor this purpose, they must be configured in such a way that asubstantially high concentration of ground-state atoms, radicals ormetastable molecules flow out of the treatment device and contact thewound.

A further exemplary embodiment of the present invention comprises amethod of wound treatment with flowing reactive gas species, wherein alight source is used to generate the reactive species. When a lightsource, such as an ultraviolet light source, is used for this purpose,the source must be configured in such a way that a substantially highconcentration of ground-state atoms, radicals, ions, or metastablemolecules flow out of the treatment device and contact the wound.

The method of the present invention comprises a step of directing thegas flow, rich in radicals and other reactive species, out of the deviceand onto the wound. In this step, it is required that the gas flowvelocity is fast enough to prevent the radicals and other reactive gasspecies from being converted back into stable molecules prior toimpinging on the wound. The lifetime of the ground-state atoms,radicals, ions, or metastable molecules in a flow of atmosphericpressure gas is generally less than 50 milliseconds, and in many cases,less than 10.0 milliseconds. Therefore, the outlet of the instrumentthat generates the reactive gas species should be placed above the woundat a distance of 0.1 to 10.0 cm, and the gas velocity at the outletshould be sufficient that the transit time from the instrument to thewound is less than about 50 milliseconds, and preferably less than 10.0milliseconds. The means of placing the apparatus above the wound maycomprise holding it in the hand, holding it with in a robotic system,mounting it in a fixture that can be positioned over the wound, ormounting it in a fixture that is attached to the patient around the areaof the wound. Other means of placing the apparatus may be used withoutdeviating from the scope of the present invention, and would be obviousto those skilled in the art.

The method of the present invention further comprises a step of exposingthe wound to the reactive gas species for a sufficient period of time tocause a therapeutic effect, wherein one of the therapeutic effects maybe to kill bacteria colonizing the wound. For the purposes of thepresent invention, a sufficient period of time may be an exposure to thereactive gas for 10.0 seconds to 1.0 hour, and generally in the range of1.0 minute to 10.0 minutes. Since the wound treatment apparatus may bescanned over the wound, the total treatment time may be longer than theaforementioned time periods. Moreover, it may be advantageous for thepatient to be treated with the wound treatment device many timesthroughout the healing process.

An exemplary embodiment of the present invention is a method of treatinginfected wounds that comprises (1) flowing gas containing moleculesthrough a device that converts the molecules into radicals and otherreactive species, (2) directing the gas flow, rich in radicals and otherreactive species, out of the device and onto the wound, and (3) exposingthe wound to the reactive species for a sufficient period of time tokill bacteria that have infected the wound. Bacteria that may beeffectively killed by the present invention comprise gram-positivebacteria, gram-negative bacteria, obligate aerobes, facultativeanaerobes, microaerophilic bacteria, obligate anaerobes, and morespecifically, Streptococcus pyogenes, Staphylococcus aureus, Clostridiumperfringens, Pseudomonas aeruginosa, Pseudomonas cepacia, Bacillusanthracis, Streptococcus viridans, Staphylococcus epidermidis,Clostridium tetani, Xanthomonas maltophillia, Bacteroides fragilis,Bacterioides melaminogenicus, Fusobacterium, Yersiniai enterocolitica,Francisella tularensis, Pasteurella multocida, Treponema pallidum,Treponema pertenue, Mycobacterium leprae, Salmonella typhi, andSerratia. However, embodiments of the invention are not limited toeliminating these bacteria.

Another exemplary embodiment of the present invention is a method oftreating wounds that comprises (1) flowing gas containing moleculesthrough a device that converts the molecules into radicals and otherreactive species, (2) directing the reactive gas flow out of the deviceand onto the wound, (3) exposing the wound to the reactive species for asufficient period of time to cause a therapeutic effect, and (4)treating the wound with a second therapeutic compound intermittentlyduring the time the wound is exposed to the reactive gas flow. Thetherapeutic effect may include killing bacteria, destroying bacterialbiofilms, and stimulating regeneration of damaged tissue. The secondtherapeutic compound that is provided to the wound during the treatmentprocess includes but is not limited to saline solution, antimicrobialagents, proteins or enzymes that target specific bacteria and are lethalto them, drugs, proteins or enzymes that stimulate the regeneration oftissue, and drugs, proteins or enzymes that strengthen the immune systemof the patient in the effected region.

In the foregoing embodiment of the present invention, many differentmethods may be used to apply the second therapeutic compound, includingbut not limited to introducing the compound into a gas that is made toflow over the wound, blotting the wound with a sterile gauze pad that iscoated with the compound, spraying the wound with a liquid aerosolcontaining the compound, applying a solution containing the compound tothe wound with a needle and syringe, or using any other practical meansof application that would be obvious to those skilled in the art.

11.0 Use of Low Temperature, Atmospheric Pressure Plasmas for TreatingWounds

As previously described, embodiments of the invention may involve use ofa low temperature, atmospheric pressure plasma for treating wounds,wherein the plasma generates a substantially high concentration ofground-state atoms, radicals, ions or metastable molecules that flow outof the device and directly contact the wound. Atmospheric pressureplasma devices that are suitable for this embodiment are those that canbe held by hand or mounted on a stage and easily manipulated by hand orrobot over the wound surface. An exemplary embodiment of the presentinvention is a low temperature, atmospheric pressure plasma for treatingwounds, wherein the plasma is generated by flowing gas into and out of ahousing that contains closely spaced electrodes, and by applying radiofrequency power to at least one of the electrodes sufficient tobreakdown the gas and form a capacitive discharge. Radio frequenciesthat are suitable for this embodiment of the invention equal n times13.56 megahertz (MHz), where n is an integer from 1 to 10. A suitablespacing between the electrodes is from 0.2 to 5.0 millimeters, andpreferably between 0.5 and 2.0 millimeters, although other spacingscould be used and remain within the scope of the present invention.

Another exemplary embodiment of the present invention is the use of alow temperature, atmospheric pressure plasma for treating wounds,wherein the plasma is generated by flowing a mixture of inert gas, suchas argon or helium, and a molecular gas, such as oxygen, carbon dioxide,or nitrous oxide, into and out of a housing that contains closely spacedelectrodes, and by applying radio frequency power to at least one of theelectrodes sufficient to breakdown the gas and form a capacitivedischarge. In this embodiment of the present invention, a preferred gasmixture would be helium or argon and between 0.1 and 10.0 volume percentoxygen, and more preferably between 0.5 and 5.0 volume percent oxygen.In another embodiment of this invention, a preferred gas mixture wouldbe helium or argon and between 0.1 and 10.0 volume percent carbondioxide or nitrous oxide, and more preferably between 0.5 and 5.0 volumepercent carbon dioxide or nitrous oxide.

Embodiments of the invention may further involve the use of a lowtemperature, atmospheric pressure plasma for treating infected wounds,wherein the ground-state atoms, radicals, ions or metastable moleculesgenerated by the plasma directly contact the wound and kill thefollowing microorganisms: gram-positive bacteria, gram-negativebacteria, obligate aerobes, facultative anaerobes, microaerophilicbacteria, obligate anaerobes, and more specifically, Streptococcuspyogenes, Staphylococcus aureus, Clostridium perfringens, Pseudomonasaeruginosa, Pseudomonas cepacia, Bacillus anthracis, Streptococcusviridans, Staphylococcus epidermidis, Clostridium tetani, Xanthomonasmaltophillia, Bacteroides fragilis, Bacterioides melaminogenicus,Fusobacterium, Yersinia enterocolitica, Francisella tularensis,Pasteurella multocida, Treponema pallidum, Treponema pertenue,Mycobacterium leprae, Salmonella typhi, and Serratia. However,embodiments of the invention are not limited to eliminating thesemicroorganisms.

The foregoing description, including the preferred embodiments of theinvention, has been presented for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise form disclosed. Many modifications andvariations are possible in light of the above teaching. The abovespecification provides a complete description of the apparatus, methodand use of the invention.

What is claimed is:
 1. An apparatus comprising: a plasma generatingdevice for producing a flow of gas comprising at least one reactive gasspecies in a low temperature, atmospheric pressure plasma, the flow ofgas comprising mixing an inert gas and a reactive gas provided by a gasflow system; a nozzle coupled to the plasma generating device fordelivering the at least one reactive gas species to a wound; and aproximity sensor for providing a feedback signal indicating proximity ofthe nozzle to the wound.
 2. The apparatus of claim 1, wherein the lowtemperature, atmospheric plasma is generated by applying radio frequencypower to at least one of closely spaced electrodes sufficient tobreakdown the gas and form a capacitive discharge, the closely spacedelectrodes comprising a first surface of a first electrode and a secondsurface of a second electrode machined into the same shape forming auniform gap between the surfaces in contact with the gas flow where thelow temperature, atmospheric pressure plasma is generated.
 3. Theapparatus of claim 1, wherein the inert gas is selected from the groupconsisting of argon and helium.
 4. The apparatus of claim 1, wherein theat least on reactive gas species comprises oxygen containing gasmolecules and the reactive gas is selected from the group consisting ofair, carbon dioxide, carbon monoxide, nitrous oxide, ammonia, and water.5. The apparatus of claim 1, wherein the gas flow comprises mixing 0.1to 10.0 volume % of the reactive gas in the inert gas.
 6. The apparatusof claim 1, further comprising a control unit coupled to the plasmagenerating device for supplying a rate and gas composition of the gasflow and electric power to the plasma generating device for generatingthe at least one reactive gas species.
 7. The apparatus of claim 6,wherein the control unit is operated such that the at least one reactivegas species has a transit time from the nozzle to the wound of less thanabout 50 milliseconds.
 8. The apparatus of claim 1, wherein the nozzlecomprises a shape selected from the group consisting of a disc, arectangle, a cone, and a hemisphere, wherein the shape has at least oneopening for the at last one reactive gas species to flow out.
 9. Theapparatus of claim 1, further comprising a robotic arm coupled to theplasma generating device for scanning the at least one reactive gasspecies over the wound.
 10. The apparatus of claim 1, further comprisinga cooling system including a cooling fluid circulating around the nozzleto cool the flow of the gas.
 11. The apparatus of claim 1, wherein theat least one reactive gas species is selected from the group consistingof oxygen atoms, nitrogen atoms, hydrogen atoms, and hydroxyl radicals.12. The apparatus of claim 1, wherein the nozzle includes a chemicaloutlet for delivering a chemical compound to the wound.
 13. Theapparatus of claim 12, wherein the at least one reactive gas speciescauses the chemical compound to bond to cells of the wound.
 14. A methodcomprising: flowing a gas comprising mixing an inert gas and a reactivegas provided by a gas flow system; generating a low temperature,atmospheric pressure plasma with a plasma generating device; forming inthe low temperature, atmospheric pressure plasma at least one reactivegas species; delivering the at least one reactive gas species to a woundthrough a nozzle coupled to the plasma generating device; and providinga feedback signal indicating proximity of the nozzle to the wound with aproximity sensor.
 15. The method of claim 14, wherein the lowtemperature, atmospheric plasma is generated by applying radio frequencypower to at least one of closely spaced electrodes sufficient tobreakdown the gas and form a capacitive discharge, the closely spacedelectrodes comprising a first surface of a first electrode and a secondsurface of a second electrode machined into the same shape forming auniform gap between the surfaces in contact with the gas flow where thelow temperature, atmospheric pressure plasma is generated.
 16. Themethod of claim 14, wherein the inert gas is selected from the groupconsisting of argon and helium.
 17. The method of claim 14, wherein theat least on reactive gas species comprises oxygen containing gasmolecules and the reactive gas is selected from the group consisting ofair, carbon dioxide, carbon monoxide, nitrous oxide, ammonia, and water.18. The method of claim 14, wherein the gas flow comprises mixing 0.1 to10.0 volume % of the reactive gas in the inert gas.
 19. The method ofclaim 14, further comprising supplying a rate and gas composition of thegas flow and electric power to the plasma generating device forgenerating the at least one reactive gas species with a control unitcoupled to the plasma generating device.
 20. The method of claim 19,wherein the control unit is operated such that the at least one reactivegas species has a transit time from the nozzle to the wound of less thanabout 50 milliseconds.
 21. The method of claim 14, wherein the nozzlecomprises a shape selected from the group consisting of a disc, arectangle, a cone, and a hemisphere, wherein the shape has at least oneopening for the at last one reactive gas species to flow out.
 22. Themethod of claim 14, further comprising a robotic arm coupled to theplasma generating device for scanning the at least one reactive gasspecies over the wound.
 23. The method of claim 14, further comprisingcirculating a cooling fluid around the nozzle with a cooling system tocool the flow of the gas.
 24. The method of claim 14, wherein the atleast one reactive gas species is selected from the group consisting ofoxygen atoms, nitrogen atoms, hydrogen atoms, and hydroxyl radicals. 25.The method of claim 14, wherein the nozzle includes a chemical outletfor delivering a chemical compound to the wound.
 26. The method of claim25, wherein the at least one reactive gas species causes the chemicalcompound to bond to cells of the wound.
 27. An apparatus comprising:means for flowing a gas comprising mixing an inert gas and a reactivegas; means for generating a low temperature, atmospheric pressure plasmafrom the flowing gas that contains at least one reactive gas species;and means for delivering the at least one reactive gas species to awound; wherein the low temperature, atmospheric plasma is generated byapplying radio frequency power to at least one of closely spacedelectrodes sufficient to breakdown the gas and form a capacitivedischarge, the closely spaced electrodes comprising a first surface of afirst electrode and a second surface of a second electrode machined intothe same shape forming a uniform gap between the surfaces in contactwith the gas flow where the low temperature, atmospheric pressure plasmais generated; and a proximity sensor means for providing a feedbacksignal indicating proximity of the means for delivering to the wound.